1. Field of the Invention
The present invention relates to an automatic teller machine (ATM) and, more particularly, to an apparatus and method for detecting an occluded face and an apparatus and method for discriminating an illegal user using the same, for an ATM.
2. Description of the Related Art
With recent developments in automation technology, cash dispensers or automatic teller machines (ATMs) have been used in a rapidly growing number of financial institutions. At the same time, there has been an increase in financial crimes in which cash or a check is illegally withdrawn using another person's credit card or passbook and personal identification number. To deter these financial crimes, financial institutions photograph and record transactions of all users with a camera mounted in an ATM and identify the face of an illegal user using a recording medium having the transactions recorded thereon. However, since illegal users usually commit financial crimes while preventing their faces from being photographed, it is difficult to accurately identify the faces of the illegal users using common photographing methods.
Korean Patent Publication Nos. 1998-82154 and 2000-61100 disclose techniques for controlling a user's access to service equipment connected to a monitoring system. According to Korean Patent Publication No. 1998-82154, a user's facial image is obtained from a monitoring camera for recording users' facial images in response to the operation of an ATM, it is checked whether confirmable feature points exist through an analysis of the obtained image, and a user's request is processed only when the presence of the feature points is confirmed. According to Korean Patent Publication No. 2000-61100, it is determined if images of the eyes and the mouth are accurately detected in a photographed facial image of a user and the operation of an ATM is stopped to prevent cash or a check from being withdrawn if the images of the eyes and the mouth are not accurately detected, thereby preventing financial crimes from occurring. In this situation, the images of the eyes and the mouth are not accurately detected when a user blocks a portion of the face with a hand, the face is inclined at an extreme angle, the user puts a cap across the face, the user wears a mask, or the user wears sunglasses that are very dark and are much larger than the sizes of the eyes.
However, in the techniques enclosed in the above-mentioned patent publications, when a user wears sunglasses or it is determined that occlusion occurs in an eye region due to the generation of a dark portion caused by shadows around the eyes, the sunglasses or the dark portion are recognized as normal eyes which happen to be larger than the user's actual eyes. Consequently, it is difficult to detect feature points of eyes. Moreover, since, unlike eyes, definitions of feature points of a nose and a mouth are insufficiently specific and a nose region and a mouth region are sensitive to illumination, the feature points of a nose and a mouth significantly change from case to case.